Setter assembly for additive manufacturing

ABSTRACT

A method includes assembling a setter assembly onto a binder-jet printed part, wherein the setter assembly includes a base, a top setter, a bottom setter positioned between the base and the top setter, and a support pin extending between the base and the top setter having a terminus that abuts an inward facing surface of the top setter, such that at least portion of the binder-jet printed part is nested between the top setter and the bottom setter. The method includes heating the binder-jet printed part and the setter assembly to debind or sinter the binder-jet printed part, wherein a length of the support pin decreases in response to the heating to move the top setter toward the base.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/001,565 entitled “SETTER ASSEMBLY FOR ADDITIVE MANUFACTURING,” filedJun. 6, 2018, which is incorporated by reference herein in its entiretyfor all purposes.

BACKGROUND

The subject matter disclosed herein relates to additive manufacturing,and more particularly, to support structures used to support printedparts during post-printing thermal processing.

Additive manufacturing, also known as 3D printing, generally involvesprinting an article one layer at a time using specialized systems. Inparticular, a layer of a material (e.g., a metal and/or ceramic powderbed) is generally deposited on a working surface and bonded with anotherlayer of the same or a different material. Additive manufacturing may beused to manufacture articles (e.g., fuel nozzles, fuel injectors,turbine blades, etc.) from computer aided design (CAD) models usingtechniques such as, but not limited to, metal laser melting, lasersintering, and binder jetting. These additive manufacturing techniquesmelt, sinter, and/or chemically bind layers of material to generate thedesired article. Additive manufacturing facilitates manufacturing ofcomplex articles and enables enhanced flexibility for customization ofarticles compared to other manufacturing techniques, such as molding(e.g., cast molding, injection molding). Additionally, additivemanufacturing can reduce the overall manufacturing costs associated withgenerating these complex articles compared to molding techniquesgenerally used.

BRIEF DESCRIPTION

In one embodiment, a setter assembly for use in additive manufacturing abinder-jet part includes a base, a first setter component having a firstsetter portion and a second setter portion that may be removably coupledto the first setter portion and a plurality of protrusions disposed onand extending away from a surface of the base. The plurality ofprotrusions may align the base with the first setter component andenable coupling of the first setter component to the base. The setterassembly also includes a second setter component positioned between thebase and the first setter component. The second setter component isdisposed on the surface and the first setter component, the secondsetter component, and the base can be assembled onto a printed part suchthat at least a portion of the printed part is nested between the firstsetter component and the second setter component.

In a second embodiment, a part manufactured via a binder-jet printingprocess includes the steps of heating a green body part formed from aplurality of printed layers above a first temperature to remove thebinder used to print the part and generate a brown body part andcoupling a setter assembly to the brown body part. The setter assemblyincludes a base, a top setter, a bottom setter positioned between thebase and the top setter, and a plurality of support pins extendingbetween the base and the top setter such that a terminus of each supportpin of the plurality of support pins abuts an inward facing surface ofthe top setter, and a portion of the brown body part is positioned abovethe top setter, while another portion of the brown body is nestedbetween the top setter and bottom setter. The binder-jet printingprocess further includes the step of heating the brown body part and thesetter assembly above a second temperature to sinter the powder togenerate the part. The setter assembly may support one or more regionsof the brown body part to block distortion of the brown body part duringheating to generate the part.

In a third embodiment, a method for additive manufacturing of a partincludes assembling a setter assembly onto a binder-jet printed part.The setter assembly includes a base, a first setter component, a secondsetter component positioned between the base and the first settercomponent, and support pins extending between the base and the firstsetter component. A terminus of the support pins abuts an inward facingsurface of the first setter component and at least a portion of theprinted part is nested between the first setter component and the secondsetter component. The method also includes heating the printed part andthe setter assembly to debind or sinter the binder-jet printed part. Alength of the support pins decreases in response to thermal processingof the binder-jet printed part to enable movement of the first settercomponent toward the second setter component. The method furtherincludes disassembling and removing the setter assembly from thethermally-processed part.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood when the following detaileddescription is read with reference to the accompanying drawings in whichlike characters represent like parts throughout the drawings, wherein:

FIG. 1 is a block diagram of an embodiment of a binder-jet printer usedto print a part having internal channels;

FIG. 2 is a flow diagram of an embodiment of a method of manufacturing aarticle via a binder-jet printing process that uses a setter assembly tosupport a printed part during a post-printing thermal process used togenerate the article;

FIG. 3a is a perspective view of an embodiment of a setter assembly thatmay be used in performing the method of FIG. 2, wherein the setterassembly includes a top setter component, a core, a bottom settercomponent, and base;

FIG. 3b is a perspective view of an embodiment of the setter assembly ofFIG. 3a assembled onto the printed part;

FIG. 4 is a perspective view of an embodiment of a portion of the topsetter component of the setter assembly of FIG. 3, wherein the topsetter component is partially assembled on the printed part;

FIG. 5 is a perspective view of an embodiment of the top settercomponent of the setter assembly of FIGS. 3 and 4 assembled on theprinted part;

FIG. 6 is a top view of an embodiment of the printed part having anairfoil and the core of the setter assembly positioned within theairfoil;

FIG. 7 is a cross-sectional side view of an embodiment of the setterassembly and printed part of FIG. 3b before and after sintering; and

FIG. 8 is a cross-sectional front view of an embodiment of the setterassembly and printed part of FIG. 3b before and after sintering.

DETAILED DESCRIPTION

One or more specific embodiments will be described below. In an effortto provide a concise description of these embodiments, all features ofan actual implementation may not be described in the specification. Itshould be appreciated that in the development of any such actualimplementation, as in any engineering or design project, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time consuming, but would nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

When introducing elements of various embodiments of the presentinvention, the articles “a,” “an,” “the,” and “said” are intended tomean that there are one or more of the elements. The terms “comprising,”“including,” and “having” are intended to be inclusive and mean thatthere may be additional elements other than the listed elements.Furthermore, any numerical examples in the following discussion areintended to be non-limiting, and thus additional numerical values,ranges, and percentages are within the scope of the disclosedembodiments.

There are numerous techniques for manufacturing articles, such as metaland ceramic parts used in a variety of machinery. For example, moldingtechniques, such as sand molding, cast molding, and/or injectionmolding, among others, may be used to manufacture metal and ceramicparts for machinery applications. As noted above, other techniques thatmay be used to manufacture metal and ceramic parts include additivemanufacturing. For example, additive manufacturing techniques that maybe used to manufacture articles include, but are not limited to, lasermelting, laser sintering, and binder jetting. Additive manufacturing canbe advantageous for fabricating parts compared to molding techniquesdue, in part, to the increased flexibility of materials that may beused, the enhanced ability to manufacture complex articles, and reducemanufacturing costs.

Unlike laser melting and laser sintering additive manufacturingtechniques, which heat the material to consolidate and build layers ofthe material to form a printed part (e.g., metal or ceramic part),binder jetting uses a chemical binder to bond particles of the materialinto layers that form a green body of the printed part. As definedherein, the green body of the printed part (or green body part) isintended to denote a binder-jet printed part that has not undergone heattreatment to remove the chemical binder. During manufacturing, thechemical binder (e.g., a polymeric adhesive) is selectively depositedonto a powder bed in a pattern representative of a layer of the partbeing printed. Each printed layer is cured (e.g., via heat, light,moisture, solvent evaporation, etc.) after printing to bond theparticles of each layer together to form the green body part. After thegreen body part is fully formed, the chemical binder is removed to forma brown body part. As defined herein, the brown body of the printed part(or brown body) is intended to denote a printed part that has undergoneheat treatment to remove the chemical binder. Following removal of thechemical binder, the brown body part is sintered to consolidate thebuild layers and form a consolidated part.

In certain post-printing thermal processes (e.g., heat treatment,sintering), the brown body part may be heated to temperatures aboveapproximately 1000 degrees Celsius (° C.) to enable consolidation of thematerial (e.g., metal or ceramic particles) in the build layers. Asdefined herein, post-printing thermal processing is intended to denote athermal process that includes heating the printed part to a temperatureabove a debinding temperature (e.g., above 200° C.). During heattreatment, the brown body part undergoes thermally induced processesthat may result in distortion of the brown body part during thermalprocessing. For example, sintering the brown body part to consolidatethe build layers causes volumetric shrinkage and densification of thebrown body part to form the consolidated part. The shrinkage of thebrown body part may result in distortion of certain structural features(e.g., an overhang, airfoil, or the like). Additionally, gravitationalforces may induce warping or sagging of certain structural features ofthe brown body part during thermal processing. The distortion of thebrown body part may affect the overall geometry of the consolidated partin a manner that renders the consolidated part unsuitable for use.Printed parts having complex geometries may be more prone to thermallyinduced distortions compared to printed parts have simple andnon-complex geometries. It is presently recognized that distortion ofprinted parts having complex geometries or expected to have a largeamount of distortion (e.g., greater than approximately 20% distortion)may be mitigated by using a support that allows for dimensional changesduring heat treatment to form the consolidated part.

Disclosed herein are setter assemblies that may be used to providesupport to binder-jet printed parts during post-printing thermalprocessing to facilitate manufacture of parts having complex geometries.As discussed in further detail below, the setter assemblies disclosedherein are assembled onto the printed part prior to sintering. Thesetter assemblies provide support to regions of the printed part thatmay be prone to thermally induced distortion. The setter assemblies alsoallow for dimensional changes of the printed part resulting fromdensification (e.g., consolidation of printed layers) of the printedpart to form the consolidated part. A geometry of the setter assembliesmay be based on a geometry of the printed part. That is, the setterassemblies disclosed herein include structural features that arecomplimentary to certain structural features of the printed part. Assuch, the printed part is properly positioned and supported by therespective setter assembly. Additionally, the setter assembly mayinclude features that facilitate assembly onto the printed part anddisassembly to remove (e.g., separate) the setter assembly from theconsolidated part. Disassembly and separation of the setter assemblyfrom the printed part is done in a manner that does not affect theintegrity of the consolidated part. Therefore, the presently disclosedsetter assemblies may be used to mitigate distortion (of printed partshaving complex geometries) during post-printing thermal processing,which can reduce manufacturing cost and improve production yields.

With the foregoing in mind, FIG. 1 is a block diagram of a binder jetprinter 10 that may be used to print a part that can be coupled to asetter assembly to support certain structural features of the printedpart during thermal processes. In operation, the binder jet printer 10selectively deposits a binder into the portion of a layer 12 of powder(e.g., metal and/or ceramic) that is used to print an additivelymanufactured part, in accordance with embodiments of the presentapproach. In the illustrated embodiment, the binder jet printer 10includes a working platform 16 (e.g., a stage) that supports the layerof powder 12, a reservoir 18 that stores a binder solution 20 having abinder 24 and/or or binder precursor 25, a printer head 30 that isfluidly coupled to the reservoir 18, and a powder deposition system 32that deposits a powdered material 34 to form the layer 12 of powder. Thebinder precursor 25 includes monomers that may be polymerized in situ onthe layer of powder 12 after deposition to form the binder 24. Thebinder solution 20 may include additional components such as, but notlimited to, wetting agents, viscosity modifiers, or the like. Theprinter head 30 selectively deposits the binder solution 20 into thelayer of powder 12 to print (e.g., selectively deposit) the binder 24onto and into the layer 12 in a pattern that is representative of thelayer of the part being printed.

The illustrated binder jet printer 10 includes a control system 36 thatcontrols operation of the binder jet printer 10. The control system 36may include a distributed control system (DCS) or any computer-basedworkstation that is fully or partially automated. For example, thecontrol system 36 can be any device employing a general purpose computeror an application-specific device, which may generally include memorycircuitry 38 storing one or more instructions for controlling operationof the binder jet printer 10. The memory 38 may also store CAD designsrepresentative of a structure of the article being printed. Theprocessor may include one or more processing devices (e.g.,microprocessor 40), and the memory circuitry 38 may include one or moretangible, non-transitory, machine-readable media collectively storinginstructions executable by the processing device 40 to enable thefunctionality described herein.

FIG. 2 is a block diagram depicting a method 50 for manufacturing anarticle via binder-jet manufacturing process using the setter assemblydisclosed herein to provide support for a printed part (e.g., a greenand/or a brown body part) during post-printing processing, in accordancewith embodiments of the present approach. Certain aspects of the method50 are executed by the processor 40 according to instructions stored inthe memory 38 of the control system 36. The illustrated embodiment ofthe method 50 begins with depositing (block 52) the layer 12 of thepowder that is used to manufacture an article of interest. For example,the layer 12 of the powdered material 34 (e.g., metallic and/ornon-metallic powder) is deposited on a working surface to form a powderbed. As used herein, a “working surface” is intended to denote a surfaceonto which a powder bed layer or a binder solution may be deposited ontoduring binder jet printing processes. The working surface may include aworking platform of a binder jet printer, a layer of powder, or a binderprinted layer. For example, referring back to FIG. 1, in certainembodiments, the working surface may be the working platform 16 of thebinder jet printer 10 (e.g., when the layer 12 is the first layer of thegreen body part). In other embodiments, the working surface may be apreviously printed layer. The powdered material 34 may be deposited ontothe working surface using the powder deposition system 32. In certainembodiments, the powder deposition system 32 deposits the layer 12 suchthat the layer 12 has a thickness of between approximately 10 microns(μm) and approximately 200 μm (e.g., approximately 40 μm or less).However, in other embodiments, the thickness of the layer 12 may be anysuitable value.

The part to be printed may include a variety of parts having complex, 3Dshapes, such as, but not limited to, fuel tips, fuel nozzles, shrouds,micro mixers, turbine blades, or any other suitable part. Therefore, thepowdered material 34 used to print the article may vary depending on thetype of article and the end use of the article (e.g., gas turbineengines, gasification systems, etc.). The material 34 may includemetallic and/or non-metallic materials. By way of non-limiting example,the material 34 may include: nickel alloys (e.g., Inconel 625, Inconel718, René 108, René 80, René 142, René 195, and René M2, Marm-247);cobalt alloys (e.g., Hans 188 and L605); cobalt-chromium alloys, castalloys: (e.g., X40, X45, and FSX414), titanium alloys, aluminum-basedmaterials, tungsten, stainless steel, metal oxides, nitrides, carbides,borides, aluminosilicates, ceramics, or any other suitable material andcombinations thereof. In certain embodiments, the material 34 includesparticles having a particle size distribution (e.g., d₅₀) that isbetween approximately 1 micron (μm) and approximately 75 μm. However, inother embodiments, the material 34 may utilize particles of any othersuitable particle size distribution.

Returning to FIG. 2, following deposition of the layer of powder 12, themethod 50 continues with selectively depositing (block 54) the binder 24into portions of the layer 12 according to a predetermined pattern togenerate a binder printed layer of powder 58. For example, asillustrated in FIG. 1, the binder 24 may be selectively printed into thelayer of powder 12 using the printer head 30. As mentioned, the printerhead 30 is generally controlled (e.g. operated, guided) by the controlsystem 36 based on a CAD design, which includes a representation of thelayer 12 of the part being printed.

The binder 24 coats particles in the powder layer 12, thereby generatingbinder-coated particles within the powder layer 12. As discussed below,after curing (e.g., via solvent evaporation, exposure to moisture,exposure to light), the binder 24 bonds the binder-coated particles(e.g., to one another, to the working surface) according to the printedpattern of binder solution 20 to form the binder printed layer of powderof a green body part 60, as indicated in FIG. 1.

The binder 24 may be selected from a class of thermoplastic or thermosetpolymers that include, but are not limited to, polymers derived fromunsaturated monomers. For example, the binder 24 may one or morepolymers have the following formulas: (CH₂CHR)_(n), where R=a proton(—H), hydroxyl (—OH), phenyl, alkyl, or aryl unit. The binder 24 mayalso include one or more mono-functional acrylic polymers having theformula (CH₂—CR²COOR¹)_(n), where R¹=an alkyl or aryl unit, and R²=a —Hor methyl (—CH₃) unit; di-acrylic polymers having the formula[(CH₂—CR²COO)₂—R³]n, where R²=a —H or —CH₃ unit and R³=a divalenthydrocarbon radical; tri-acrylic polymers having the following formula[(CH₂CR¹COO)₃—R⁴]_(n), where R¹=—H or —CH₃ and R⁴=a trivalenthydrocarbon radical and/or poly(alkylene carbonates) includingco-polymeric alkylene carbonates, such as poly(ethylene-cyclohexenecarbonate), poly(ethylene carbonate), poly(propylene carbonate,poly(cyclohexane carbonate), among others. In certain embodiments, thebinder 24 may include poly(methylmethacrylate) (PMMA), polystyrene (PS),poly(vinyl alcohol) (PVA); poly(alkylene carbonates), for example QPAC®25, 40, 100, and 130 from Empower Materials (located in New Castle,Del.), and polymers derived from hexanediol diacrylate (HDDA),trimethylolpropane triacrylate (TMPTA, for example, SR351 from Sartomerof Exton, Pa.), and diethylene glycol diacrylate (DGD).

As discussed above with reference to FIG. 1, the printer head 30receives the binder solution 20 (e.g., ink) having the binder 24 andselectively prints (e.g., deposits, flash vaporizes and condenses) thebinder 24 into portions of the layer of powder 12. Accordingly, thebinder solution 20 may have certain properties that facilitate binderjet printing via the printer head 30. The binder solution 20 may includeadditives that facilitate deposition of the binder 24 into the layer 12.For example, in certain embodiments, the binder solution 20 includes oneor more additives, including but not limited to: viscosity modifiers,dispersants, stabilizers, surfactants (e.g., surface active agents) orany other suitable additive that may facilitate jettability of thebinder solution 20 and selective deposition of the binder 24 into thepowder layer 12.

For example, in certain embodiments, the binder solution 20 may includesurfactants. The surfactants may be ionic (e.g., zwitterionic, cationic,anionic) or non-ionic, depending on the properties of the binder 24and/or the material 34, in different embodiments. By way of non-limitingexample, the surfactant may be polypropoxy diethyl methylammoniumchloride (e.g., VARIQUAT® CC-42NS, available from Evonik located inEssen, Germany) and/or a polyester/polyamine condensation polymer (e.g.,Hypermer KD2, available from Croda Inc. located in Snaith, UnitedKingdom), in certain embodiments. In certain embodiments, the one ormore additives may improve the wettability of the material 34 tofacilitate coating the particles of the powder with the binder 24. Theone or more additives may also change (e.g., modify) the surface tensionof the binder solution 20 to facilitate jettability of the bindersolution 20. For example, in certain embodiments, the binder solution 20is generally considered jettable if the Ohnesorge number (e.g., theratio of viscous forces to inertial and surface tension forces) isbetween approximately 0.1 and approximately 1.

In certain embodiments, the one or more additives may also include asolvent that dissolves the binder 24. The solvent may be aqueous ornon-aqueous, depending on the selected binder 24, as well as otheradditives that may be in the binder solution 20. The solvent isgenerally non-reactive (e.g., substantially inert) such that it does notreact with the powder material 34, the binder 24, or any other additivesthat may be in the binder solution 20. Additionally, in general, thesolvent should readily evaporate after selective deposition of thebinder 24 into the powder layer 12, which may facilitate curing to bondtogether the binder-coated particles of the printed layers 53. Examplesolvents of the binder solution 20 include, but are not limited to,water, methylene chloride (CH₂Cl₂), chloroform (CHCl₃), toluene,xylenes, mesitylene, anisole, 2-methoxy ethanol, butanol, diethyleneglycol, tetrahydrofuran (THF), methyl ethyl ketone (MEK),trichloroethylene (TCE), or any other suitable solvent.

Following deposition of the layer 12 and the selective printing of thebinder 24, as set forth in blocks 52 and 54 of FIG. 2, the illustratedmethod 50 continues with curing (block 62) the binder 24 to form a curedlayer of the green body part 60. For example, as discussed above, theselectively deposited binder solution 20 may be a mixture of the binder24 (e.g., polymer) and a solvent. While a portion of the solvent in thebinder solution 20 may be evaporated during deposition (e.g., printing)of the binder 24, a certain amount of the solvent may remain within thelayer of powder 12. Therefore, in certain embodiments, the green bodypart 60 may be thermally cured (in a subsequent, post-print step) at atemperature that is suitable for evaporating the solvent remaining inthe printed layer 58 and allows for efficient bonding of the printedlayers 58 of the green body part 60.

In certain embodiments, the layer of the green body part 60 may be curedvia polymerization, wherein reactive monomers in the binder solution 20polymerize to yield the binder 24. For example, the binder 24 may bepolymerized in situ after selectively printing the binder solution 20into the powder layer 12. Following deposition of the binder solution20, the one or more binder precursors 25 (e.g., polymerizable monomers)in the binder solution 20 may be cured (e.g., reacted, cross-linked,polymerized) to form the printed layer 58 of the green body part. Forexample, in certain embodiments, the printed layer 58 may be exposed toheat, moisture, light, or any other suitable curing method thatpolymerizes the binder precursors 25 in the binder solution 20 to formthe binder 24 in the printed layer 58. In certain embodiments, thebinder solution 20 may include a radical initiator (e.g.,azobisisobutyronitrile (AIBN)) to facilitate polymerization of the oneor more polymerizable monomers. In one embodiment, the binder solution20 includes binder precursors selectively deposited into the powderlayer 12 that cure (e.g., polymerize, cross-link) rapidly (e.g., on theorder of seconds) without addition supplied energy.

The method 50 typically involves the repetition of the acts of blocks52, 54, and 62 to continue fabricating in a layer-by-layer manner untilall of the layers of the entire green body part 60 have been printed.The binder 24 bonds (e.g., adheres, anchors, binds) each successivelayer and provides a degree of strength (e.g., green strength) to theprinted article to improve the integrity of the structure of the greenbody part during post-printing processes (e.g., debinding, sintering,etc.). That is, the green strength provided by the binder 24 maintainsbonding between the powder material 34 within each of the layers, andblocks (e.g., resists, prevents) delamination of the layers duringhandling and post-printing processing of the green body part 60.

As discussed above, the printed part may be heated to temperatures above1000° C. to consolidate the layers of powder material and form theconsolidated part. The high temperatures (e.g., above 1000° C.) maycause distortions in the printed part, in particular printed parts withcomplex geometries. For example, during sintering, the printed layersare consolidated, which densifies the printed part and results in acertain degree of shrinkage. The printed part is generally porous beforeundergoing thermal processing. Therefore, consolidation of the printedlayers in the printed part during post-printing thermal processingdecreases a volume of the printed part to densify and compact theprinted layers, generating a consolidated part. Densification of theprinted part may cause certain structural features (e.g., overhangs,airfoils, or the like) of the printed part that are unsupported by otherstructural features to warp, sag, bend, deform, or otherwise change theoverall geometry of the printed part. The distortions in the geometrymay render the printed part unsuitable for use. The distorted printedpart may be discarded, decreasing yields and increasing cost. Therefore,in the absence of the present disclosure, the binder jet printingprocesses for such parts may be inefficient and result in an undesirablethroughput. However, by using the setter assemblies disclosed herein tosupport the printed part (e.g., the green body part or the brown bodypart) before heating (e.g., debinding and/or sintering) may mitigatethermally induced distortions.

Accordingly, once the desired number of printed layers 58 are deposited,the method 50 includes assembling (block 61) a setter assembly onto thegreen body part 60 to provide structural support and mitigate thermallyinduced distortions of the printed part (e.g., the green body part 60and/or brown body part 68). The green body part 60 may be nested withinthe structural support. As used herein, a nested part is intended todenote a printed part that is partially or completely surrounded by astructural support such that at least a portion of an exterior surfaceof the printed part is in contact with the structural support. While theblock 61 is discussed in the context of assembling the disclosed setterassembly onto the green body part 60, present embodiments also includeassembling the setter assembly to the brown body part 68. Accordingly,the setter assemblies disclosed herein may be used to maintain theoverall shape of a printed part during densification or otherpost-printing thermal processing.

As discussed in further detail below, the disclosed setter assembliesmay include multiple separable components, which, when combined, providesupport to one or more regions of the body part 60, 68 during debindingand/or sintering. A geometry of the setter assembly and/or thecomponents in the assembly include features that facilitate assembly ofthe components onto the green body part 60 and removal from the brownbody part 68 after sintering. Additionally, the geometry of the setterassembly is such that a difference in coefficient of thermal expansionof the printed part and the setter assembly is suitable to meetdimensional requirements of the consolidated part. That is, the setterassemblies disclosed herein are designed to accommodate for dimensionalchanges of the printed part during consolidation (e.g., sintering). Incertain embodiments, the setter assemblies may include alignmentfeatures to facilitate assembly onto the printed part in a manner thatallows tolerances (e.g., dimensional changes) of the printed part to bemet during debinding and/or sintering to form the consolidated part.

Following assembly of the setter assembly 80 on the green body part 60,the method 50 includes removing (block 64) the binder 24 from theprinted green body part 60 to generate a brown body part 68. Duringremoval of the binder 24, as referred to as debinding, the green bodypart 60 is heated to break down the binder 24 into smaller compoundshaving a lower molecular weight compared to the binder 24. For example,the printed green body part 60 may be heated to a temperature that isapproximately 500° C. or less, such as between approximately 250° C. andapproximately 450° C., to facilitate removal of the binder 24. Theconditions to which the printed green body part 60 is exposed duringdebinding (e.g., removal of the binder 24 from the printed layers of theprinted green body part 60) decomposes the binder 24 into smallermolecules that may be readily released from the printed green body part60 and generates the brown body part 68 having a substantial portion(e.g., approximately 95%, approximately 96%, approximately 97%,approximately 98%) of the binder 24 removed. In certain embodiments, aportion of the binder 24 and/or decomposition products of the binder 24(e.g., oxides, such as silicon oxide) may remain in the brown body part68 and may improve bonding of the powder material 34 within the brownbody part 68, enabling an improved brown strength that maintains thestructure of the brown body part 68 during handling between debindingand sintering.

Following removal of the binder 24 from the green body part 60, themethod 50 includes sintering (block 72) the brown body part 68 toconsolidate the powder material 34 to generate a consolidated additivelymanufactured part 74. During sintering, the brown body part 68 isgenerally exposed to a concentrated source of energy (e.g., a laser,electron beam, or any other suitable energy source) that heats the brownbody part 68 and consolidates (e.g., densifies, connects) the powderedmaterial 34 of the printed layers of the brown body 68 to form theconsolidated part 74 (e.g., substantially solid part) having a densitythat is greater than the density of the brown body part 68. Sinteringimparts strength and integrity to the brown body part 68, such that theconsolidated part 74 is suitable for use in machinery for its intendedapplication (e.g., as a component of a gas turbine engine or agasification system). The sintering temperature is a temperature that isgenerally less than (e.g., approximately 30% of) a melting point of thepowdered material 34, such that the particles of the powdered material34 soften and form connections (e.g., necks or bridges) that bindtogether neighboring particles in the brown body part 68. In general,sintering temperatures may be in excess of 1000° C., depending on theproperties of the powder material 34 used to fabricate the part. Forexample, in certain embodiments, when the powdered material 34 is anickel alloy (e.g., INCONEL® 625), the sintering temperature may bebetween approximately 1250° C.-1270° C.

Following sintering of the brown body part 68 to form the consolidatedpart 74, the method 50 includes disassembly and removal (block 76) ofsetter assembly 80 from the consolidated part. For example, as discussedin further detail below, alignment pins used to removably couple thecomponents of the setter assembly may be removed to detach andfacilitate removal of the setter components from the consolidated part74.

FIG. 3a is a perspective view of an embodiment of a setter assembly 80that may be used to provide support to printed part during post-printingthermal processing (e.g., debinding, sintering). The setter assembly 80may be manufactured from any suitable material that does not react withthe materials used to fabricate the printed part. For example, thesetter assembly 80 may be manufactured from materials such as, but notlimited to, metals, ceramics, refractory materials, or the like that donot undergo dimensional changes or react with the powder material 34during heating at temperatures suitable for debinding or for sintering.In certain embodiments, one or more components of the setter assembly 80may be coated with a protective layer (e.g., a polymer layer) thatmaintains the integrity of the setter assembly 80 and allows multiplereuses of the setter assembly 80. The setter assembly 80 may becustomized to fit a respective geometry of the printed part beingsupported.

The setter assembly 80 includes a top setter component 82, a core 84,and a bottom setter component 86. The top setter component 82 mayinclude a first top portion 90 a and a second top portion 90 b that areseparable. That is, the first top portion 90 a and the second topportion 90 b are two separate pieces. However, in certain embodiments,the top setter component 82 is a single piece or unitary component. Incertain embodiments, the top portions 90 a, 90 b may be mirror images ofone another. In other embodiments, the top portions 90 a, 90 b may havedifferent features that, when combined, support regions of a printedpart (e.g., the green body part 60 and/or the brown body part 68) duringpost-printing thermal processing. The top setter component 82 mayinclude features that conform and/or outline certain structural featuresof the brown body part 68. For example, an outward facing surface 91 ofeach top portion 90 may have a curvature 92 that is similar in shape toa curvature of a top portion (e.g., the overhang 148) of the brown bodypart 68, as discussed below with reference to FIG. 3b . This mayfacilitate positioning and assembly of the top setter component 82 ontothe printed part, as discussed below.

The bottom setter component 86 includes a base 94 and a bottom setter 96positioned on a top surface 98 of the base 94. In certain embodiments,the bottom setter 96 is removably attached to the base 94. For example,the base 94 may include coupling features (e.g., fasteners, clips,recesses, protrusions, or any other suitable coupling feature) thatengage with a complementary coupling feature on a bottom surface 97(e.g., surface that abuts the top surface 98) of the bottom setter 96.By removably coupling the bottom setter 96 and the base 94, the bottomsetter 96 may be switched out depending on the geometry of the printedpart. However, in certain embodiments, the bottom setter 96 and the base94 are a single structure or unitary. Similar to the top settercomponent 82, the bottom setter 96 may include surface features thatconform to or outline structural features of the brown body part 68 tofacilitate seating the brown body part 68 within the assembled setterassembly 80. For example, in the illustrated embodiment, the bottomsetter 96 includes a curvature 99 that is representative of a curvatureassociated with the brown body par, as discussed below.

Similar to the top setter component 82, the base 94 may have a firstbottom panel 100 a and a second bottom panel 100 b, each independentlyseparable from one another. The panels 100 a, 100 b may facilitateassembly and removal of the setter assembly 80 to and from the printedpart (e.g., the green or brown body part), as discussed in furtherdetail below. Similar to the top setter component 80, the bottom panels100 a, 100 b may be mirror images of one another or may be tailor madeof a specific part to be printed. The bottom panels 100 a, 100 b mayinclude surface features that are complimentary to the top settercomponent 82 to facilitate assembly of the setter assembly 80 around andabout the printed part. In other embodiments, the base 94 is a singlecontinuous structure with no separable parts.

The base 94 includes a plurality of protrusions 104 (e.g., extensions,stanchions, posts, pin-holders, and the like) extending away from thetop surface 98. In the illustrated embodiment, the protrusions 104extend a different distance away from the top surface 98. For example,protrusions 104 a extend a first distance 106 a away from the topsurface 98 in an axial direction 108. Protrusions 104 b extend adistance 106 b away from the top surface 98 in the axial direction 108,which is less than the distance 106 a. Accordingly, the a length of theprotrusions 104 a is greater than a length of the protrusions 104 b. Thevariability in the distance 106 between the protrusions 104 facilitatesalignment of the top setter component 82 and the base 94, and allows adistance between the top setter component 82 and the base 94 to beadjusted to meet the tolerances of the printed part during and afterheating, as discussed in further detail below.

At least a portion of each protrusion 104 is hollow, thereby forming abore 110 having an opening 112 at a terminating end 114 of eachprotrusion 104. Before the setter assembly 80 is assembled onto theprinted part, alignment pins 118 may be inserted into the bore 110 ofeach respective protrusion 104 a. For example, FIG. 3b is a perspectiveview of the setter assembly 80 assembled on a binder-jet printed part120, in accordance with an embodiment of the present disclosure. Thebinder-jet printed part 120 is nested within the setter assembly 80 suchthat at least a portion of a surface of the binder-jet printed part 120is in contact with the setter assembly 80 to provide mechanical supportto regions of the binder-jet printed part 120 that may be prone todeformation during thermal processing. In the illustrated embodiment, aportion of the alignment pins 118 are disposed within respectiveopenings 122 on the top setter component 82. The top setter component 82is supported by support pins (e.g., support beams) 124. Similar to thealignment pins 118, the support pins 124 may be inserted into the bore110 of each respective protrusion 104 b. During assembly of the setterassembly 80 on the brown body part 68, the alignment pins 118 arealigned with openings 122 located along portions of the top settercomponent 82. The openings 122 extend from an inward facing surface 128to the outward facing surface 91 of the top setter component 82, therebyforming a passageway for the alignment pins 118 to be inserted through,as shown in the illustrated embodiment. In certain embodiments, thealignment pins 118 protrude out from the outward facing surface 91. Inother embodiments, a terminus of the alignment pins 118 may be flushwith or below the outward facing surface 91. The alignment pins 118 andthe support pins 124 may printed using the binder jet printer 10 fromthe powder material 34 or other similar powder material.

As discussed in further detail below, the support pins 124 abut theinward facing surface 128 of the top setter component 82 to providesupport to the regions of the top setter component 82 and facilitatemovement of the top setter component 82 toward the base 100 in adirection 132, as shown in FIG. 3a . For example, the support pins 124may be manufactured from a material that shrinks when heated to acertain temperature. As the support pins 124 shrink, the top settercomponent 82 moves in the direction 132. In this way, the setterassembly 80 may accommodate for the dimensional changes of the printedpart 120 resulting from shrinkage and densification during post-printingthermal processing.

As discussed above, the components 82, 86 and the core 84 are assembledonto a printed part to form the setter assembly 80. For example, FIG. 4is a perspective view of an embodiment of the binder-jet printed part120 (e.g., the green body part 60 or brown body part 68) and a portionof the top setter component 82. In the illustrated embodiment, theprinted part 120 includes a central body 142 having an airfoil 144, aflange-like base 146, and an overhang 148. During post-printing thermalprocessing (e.g., debinding and/or sintering), the overhang 148 maydeform or sag due, in part, to gravitational forces and/or shrinkage. Tomitigate the deformation of the overhang 148, the top setter component82 is positioned underneath the overhang 148 (e.g., between the overhang148 and the flange-like base 146). For example, during assembly of thesetter assembly 80 on the printed part 120, each top portion 90 a, 90 bis positioned on a respective side 150 of the central body 142. The topportions 90 a, 90 b are pushed in opposite directions toward one anothersuch that the central body 142 is positioned between the top portions 90a, 90 b. Each top portion 90 a, 90 b includes an abutment surface 152that engages with the respective abutment surface of the other topportion 90 a, 90 b when the top setter component 82 is assembled ontothe printed part 120, as shown in FIG. 5. The abutment surface 152 ofeach respective top portion 90 a, 90 b may include coupling featuresthat secure, or otherwise removably attach, the top portion 90 a to thetop portion 90 b, thereby assembling the top setter component 82 of thesetter assembly 80 on the printed part 120. The coupling features mayalso facilitate alignment and proper positioning of the top portions 90a, 90 b during assembly onto the printed part 120.

As illustrated in FIG. 5, the overhang 148 of the printed part 120 restson the outward facing surface 91 of the top setter component 82. Asdiscussed above, the outward facing surface 91 may include surfacefeatures (e.g., curvature 92, contours) that conform to a shape of theoverhang 148. In this way, the top setter component 82 supports theoverhang 148 during post-printing thermal processing to mitigatedeformation of the overhang 148 during heating that may be caused bygravitational forces and/or volume changes (e.g., densification).

Once the top setter component 82 is assembled onto the printed part 120,the core 84, as previously discussed with respect to FIG. 3a and thebase component 86 of the setter assembly 80 may be assembled onto theprinted part 120. However, in other embodiments, the core 84 and/or thebase component 86 may be assembled onto the printed part 120 prior toassembly of the top setter component 82. Before coupling the top settercomponent 82 to the bottom setter component 86, the alignment pins 118and the support pin 124 are inserted into the bore 110 of eachrespective protrusion 104. A length of the pins 118, 124 may bedetermined based on an amount of shrinkage (e.g., densification) of theprinted part 120 during sintering. As discussed above, the pins 124shrink during sintering to allow the top setter component 82 to move inthe direction 132 toward the bottom setter component 86 to accommodatefor dimensional changes of the printed part 120 to form the consolidatedpart.

As best shown in FIGS. 3a and 3b , during assembly, the protrusions 104a are aligned with the openings 122 on the top setter component 82, suchthat the alignment pins 118 in the protrusions 104 a are inserted into arespective opening 122, thereby coupling the top setter component 82 andthe bottom setter component 86. The support pins 124 in the protrusions104 b provide support to regions of the top setter component 82 andenable movement of the top setter component 82 toward the bottom settercomponent 86 in the direction 132 during sintering to account forshrinkage of the printed part 120.

The core 84 may be coupled to the bottom setter 96 before assembling thebottom setter component 86 on the printed part 120. However, in otherembodiments, the core 84 may be coupled to the printed part 120 beforeassembly of the setter components 82, 86 on the printed part 120. Thecore 84 is inserted into the airfoil 144 of the printed part 120 andextends from the flange-like base 146 to the overhang 148, filling thevolume of the airfoil 144. The airfoil 144 may warp or sag duringpost-printing thermal processing, thereby distorting the shape of theairfoil 144 and affecting the overall shape and properties of theprinted part 120. The core 84 provides support to the airfoil 144 andmitigates distortion that may occur during sintering or otherpost-printing thermal processing.

FIG. 6 is a top view of the printed part 120 and the core 84 within theairfoil 144. The core 84 conforms to the shape of the airfoil 144 suchthat a gap 158 is formed between an inner surface of the airfoil 144 andan outer surface of the core 84. As discussed in further detail below,the gap 158 accommodates dimensional changes of the printed part 120resulting from shrinkage to densify the printed part 120 and consolidatethe printed layers. For example, as shown in FIG. 6, the core 84 has adimension 154 that is smaller than an inner dimension 156 of the airfoil144 such that the gap 158 is formed between the core 84 and the airfoil144. The gap 158 provides a tolerance to allow for changes in thedimension 156 of the airfoil 144 resulting from shrinkage of the printedpart 120 during debinding and/or sintering. For example, the dimension156 of the airfoil 144 may decrease, thereby decreasing the gap 158between core 84 and the airfoil 144. The core 84 may be a single pieceor multiple pieces that are assembled together to form the core 84.Disassembly and removal of the core 84 from the airfoil 144 aftersintering the printed part 120 may be facilitated when the core 84 isassembled by multiple separable pieces.

As best shown in FIG. 3b the printed part 120 that is below the overhang148 is nested within the setter assembly 80 between the top settercomponent 82 and the bottom setter component 86. The flange-like base146 of the printed part 120 rests on top of the bottom setter 96. Asdiscussed above, the bottom setter 96 conforms to the structuralfeatures of the flange-like base 146. As such, the flange-like base 146may be seated within and supported by the bottom setter 96 to mitigatedistortions that may occur during post-printing thermal processing.Similar to the flange-like base 146, the overhang 148 rests on theoutward facing surface 91 of the top setter component 82. The outwardfacing surface 91 includes features that conform to structural featuresof the overhang 148 to facilitate supporting regions of the overhang 148that may be prone to distortions.

As discussed above, the setter assembly 80 provides support to certainregions of the brown body part 68 to mitigate distortion (e.g., warpingor sagging) that may be caused by gravitational forces and/ordensification of the brown body part 68. FIGS. 7 and 8 arecross-sectional views of the setter assembly 80 and the printed part 120before and after sintering. As shown in the illustrated embodiment, thesetter assembly 80 is assembled onto the brown body part 68 as discussedabove. The setter assembly 80 is designed in a manner that creates gaps170, 172 between portions of the brown body part 68 and the core 84 andthe top setter 90, respectively. The gaps 170, 172 provide a transitionwindow (e.g., a dynamic size window) for the dimensional changes of thebrown body part 68 during sintering to form the consolidated part 162.As shown in FIGS. 7 and 8, the brown body part 68 shrinks as the layersof the powder material 34 consolidate to generate the consolidated part162. Similarly, the support pins 124 shrink to move the top settercomponent 82 in the direction 132 toward the bottom setter component 96.For example, a length of the support pins 119 may shrink (e.g.,decrease) between approximately 5% and 50% during sintering of the brownbody part 68. In this way, the top setter component 82 may move relativeto the base 100 to allow for dimensional changes of the printed part,and continue to support the printed part throughout sintering totransition the brown body part 68 into the consolidated part 162. Thecurvature and shape of the top setter component 82, the core 84, and thebottom setter component 96 provide support to the brown body part 68 asit shrinks to form the consolidated part 162. The curvature and shape ofthe components 82, 86 and the core 84 provide the final curvature of theconsolidated part 162, which may be different from the curvature of thebrown body part 68, as shown in FIGS. 7 and 8.

As discussed above, after post-printing processing is complete, thesetter assembly 80 is disassembled and removed from the consolidatedpart 74, in accordance with block 76 of the method 50 of FIG. 2. Forexample, during disassembly, the alignment pins 118 may be removed fromthe respective openings 122 to decouple the top setter component 82 andthe bottom setter component 86. Once the alignment pins 118 are removed,the top portions 90 a, 90 b or the base 100 may be separated from theconsolidated part 74. In certain embodiments, the bottom settercomponent 96 is removed along with the base 100. In other embodiments,the bottom setter component 96 is separated from the consolidated partin a separate step. Following removal of the components 82, 86 and thebase 100, the core 84 may be separated from the consolidated part 74. Asdiscussed above, the core 84 may include two or more separablecomponents. During disassembly and removal, a portion of the core 84 maybe removed from a top side of the consolidated part 74 and anotherportion of the core 84 may be removed from a bottom side of theconsolidated part 74. As should be noted, the components 82, 86, thebase 100, and the core 84 may be disassembled and removed in anysuitable order. Once separated from the setter assembly 80, theconsolidated part 74 may be Hot Isotactic Pressurized (HIP) to obtainclose to full densities (density >99.9%).

As discussed above, the setter assembly disclosed herein may be used incontinuous additive manufacturing systems to provide support to abinder-jet printed article, such as a metal or ceramic machine part,during post-printing thermal processing, such as debinding andsintering. The disclosed setter assembly includes separable settercomponents that may be individually arranged and assembled onto theprinted part prior to the post-printing thermal processing. The settercomponents may be designed in a manner that supports the printed partwhile also accounting for differences in the coefficient of thermalexpansion between the printed part and the setter assembly to meetdimensional changes of the printed part during the thermal processes(e.g., sintering). As such, the setter assembly mitigates distortions inthe structure of the printed part resulting from gravity induced warpingor sagging during debinding and/or densification to form theconsolidated part. Additionally, by using the disclosed setter assembly,printed parts having more complex geometries may be achieved withcontinuous additive manufacturing techniques.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

The invention claimed is:
 1. A method, comprising: assembling a setterassembly onto a binder-jet printed part, wherein the setter assemblycomprises a base, a top setter, a bottom setter positioned between thebase and the top setter, and a support pin extending between the baseand the top setter having a terminus that abuts an inward facing surfaceof the top setter, and wherein at least portion of the binder-jetprinted part is nested between the top setter and the bottom setter; andheating the binder-jet printed part and the setter assembly to debind orsinter the binder-jet printed part, wherein a length of the support pindecreases in response to the heating to move the top setter toward thebase.
 2. The method of claim 1, wherein heating comprises heating thebinder-jet printed part and the setter assembly above a firsttemperature to debind the binder-jet printed part.
 3. The method ofclaim 2, wherein heating further comprises heating the binder-jetprinted part and the setter assembly above a second temperature tosinter the binder-jet printed part.
 4. The method of claim 3, whereinthe setter assembly is configured to support one or more regions of thebinder-jet printed part to block distortion of the binder-jet printedpart during heating.
 5. The method of claim 1, comprising disassemblingand removing the setter assembly to yield a thermally-processed,binder-jet printed part.
 6. The method of claim 1, wherein the setterassembly comprises a core, and wherein assembling the setter assemblycomprises disposing the core into a hollow portion of the binder-jetprinted part between the top setter and the bottom setter.
 7. The methodof claim 6, wherein the hollow portion of the binder-jet printed partcomprises an airfoil.
 8. The method of claim 6, wherein the bottomsetter comprises an opening, and wherein assembling the setter assemblycomprises disposing at least a portion of the core into the opening ofthe bottom setter.
 9. The method of claim 1, wherein the base of thesetter assembly comprises a plurality of protrusions disposed on andextending away from a surface of the base, wherein each of the pluralityof protrusions is configured to align the base with the top setter andenable coupling of the top setter and the base.
 10. The method of claim9, wherein the plurality of protrusions is arranged along a portion ofan outer perimeter of the base.
 11. The method of claim 9, wherein theplurality of protrusions comprise a support pin protrusion, and whereinassembling the setter assembly comprises disposing the support pin inthe support pin protrusion such that the terminus of the support pinabuts the inward facing surface of the top setter.
 12. The method ofclaim 11, wherein the plurality of protrusions comprise an alignment pinprotrusion, and wherein assembling the setter assembly comprisesdisposing an alignment pin in the alignment pin protrusion of the basesuch that the alignment pin extends through an alignment pin opening ofthe top setter.
 13. The method of claim 12, wherein the alignment pinprotrusion extends a greater length from the surface of the base thanthe support pin protrusion.
 14. The method of claim 1, wherein anoutward facing surface of the top setter and the bottom setter eachcomprise a respective curvature that corresponds to a shape of arespective portion of the binder-jet printed part.
 15. The method ofclaim 1, wherein the top setter or the bottom setter is a multi-piecesetter.
 16. The method of claim 1, wherein the top setter or the bottomsetter is a unitary setter.
 17. The method of claim 1, comprisingfabricating the binder-j et printed part by: depositing a layer of apowder on a working surface of a binder-jet printer; selectivelyprinting a binder solution comprising a binder into the layer of thepowder in a pattern to generate a printed layer; and curing the binderin the printed layer to generate a layer of the binder-jet printed part,wherein the binder-jet printed part is formed from a plurality ofprinted layers.
 18. The method of claim 1, wherein the setter assemblycomprises a second support pin extending between the base and the topsetter and having a second terminus that abuts the inward facing surfaceof the top setter.